This invention relates generally to a lubrication system for the upper valve mechanism of an overhead valve engine having a horizontally disposed cylinder and vertical crankshaft.
Prior vertical crankshaft engines have included a pressure lubrication system for the upper valve mechanism utilizing crankcase breather induction of oil mist in a counter flow through two separate push rod tubes with the feeder push rod tube directly connected to the engine crankcase and the return push rod tube connected to the engine breather box which vents through a breather mechanism to the atmosphere. This lubrication system causes oil mist from the crankcase to flow up one push rod tube, circulate within the cylinder head rocker box to lubricate the valve mechanism, and then be induced by the crankcase breather into the breather box where the liquid oil is separated from the vapors. The liquid oil drains back into the crankcase and the vapors are vented to the atmosphere through the breather mechanism. Such a system is shown in U.S. Pat. No. 4,601,267.
Another prior lubrication system for an overhead valve internal combustion engine having a horizontal cylinder and also a horizontal crankshaft utilizes the oil leakage from a hydraulic valve lifter actuated by a horizontal cam shaft to pump oil through a push rod tube into one side of a rocker box divided by a vertical baffle. The rocker arms are oriented vertically on either side of the baffle. One of the rocker arms has an end in engagement with the push rod, which end is submerged in a pool of accumulated oil in the rocker box. By splashing and overflow the pool of oil in the one side of the rocker box crosses the vertical baffle to the other side of the rocker box containing the other vertically oriented rocker arm to also lubricate that side of the valve mechanism. Such a lubrication system is shown in U.S. Pat. No. 2,366,701.